Messages in this thread | | | Date | Mon, 7 Jun 2004 22:42:00 -0700 (PDT) | From | Phy Prabab <> | Subject | Re: [PATCH] Staircase Scheduler v6.3 for 2.6.7-rc2 |
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The test case is a build system that links headers (ln -s) and runs bison and flex on a couple of files. strace shows no difference between running on 2.4.23 compared to running on 2.6.7-rc2bk8s63.
Unfortuneately, I can not send this out, but I am trying to get a tet case that will demostrate this.
In the mean time, what can I do to try understand this slowdown?
Thank you for your time. Phy
--- Andrew Morton <akpm@osdl.org> wrote: > Phy Prabab <phyprabab@yahoo.com> wrote: > > > > Also please note the degredation between > > 2.6.7-rc2-bk8-s63: > > > > A: 35.57user 38.18system 1:20.28elapsed 91%CPU > > B: 35.54user 38.40system 1:19.48elapsed 93%CPU > > C: 35.48user 38.28system 1:20.94elapsed 91%CPU > > > > Interesting how much more time is spent in both > user > > and kernel space between the two kernels. Also > note > > that 2.4.x exhibits even greater delta: > > > > A: 28.32user 29.51system 1:01.17elapsed 93%CPU > > B: 28.54user 29.40system 1:01.48elapsed 92%CPU > > B: 28.23user 28.80system 1:00.21elapsed 94%CPU > > > > Could anyone suggest a way to understand why the > > difference between the 2.6 kernels and the 2.4 > > kernels? > > This is very very bad. > > It's a uniprocessor machine, yes? > > Could you describe the workload a bit more? Is it > something which others > can get their hands on? > > It spends a lot of time in the kernel for a build > system. I wonder why. > > At a guess I'd say either a) you're hitting some > path in the kernel which > is going for a giant and bogus romp through memory, > trashing CPU caches or > b) your workload really dislikes > run-child-first-after-fork or c) the page > allocator is serving up pages which your access > pattern dislikes or d) > something else. > > It's certainly interesting.
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